Gen 1 - Stochiometry Flashcards Preview

GAMSAT March 2016 > Gen 1 - Stochiometry > Flashcards

Flashcards in Gen 1 - Stochiometry Deck (28)
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1
Q

What is a molecule ?

A

The smallest unit of a compound that presents the properties of that compound.

2
Q

What is the empirical formula of a compound ?

A

The simplest whole number ratio between the numbers of atoms of different elements that make up the compound.

3
Q

What is the molecular formula of a compound ?

A

The number of the different atoms that make up a molecule

4
Q

What is Avogadro’s number ?

A

The number of atoms in 12g of the most abundant carbon isotope.

5
Q

Why do we need Avogadro’s Number ?

A

Large numbers of molecules need to be observed in reactions to bring microscopic chemical reactions to our macroscopic scale.

6
Q

How do you calculate moles of an element or compound ?

A
7
Q

What is the difference between the atomic weight of an element, and the mass of a single atom ?

A

Atomic weights are dimensionless numbers based on Carbon-12 as the reference standard Isotope. The mass of a single atom can be measured experimentally (!)

8
Q

What is an Isotope of an element ?

A

An atom of an element with the same number of protons but a different number of neutrons.

9
Q

Define atomic weight

A

The weight in grams of a mole of atoms

10
Q

Define molecular weight

A

The weight in grams of a mole of molecules

11
Q

How would you calculate % yield ?

A
12
Q

How would you calculate theoretical yield ?

A

Theoretical yield is the calculated amound of product that can be predicted from a balanced chemical equation.

13
Q

Give two examples of double replacement reactions

A
  1. Precipiation
  2. Acid-Base neutralisation
14
Q

Define Oxidation

A
  • An increase in Oxidation number
    OR
  • Loss of one or more electrons

(Oxidation Is Loss)

15
Q

Define Reduction

A
  • Decrease in Oxidation number
    OR
  • Gain of one or more electrons

(Reduction Is Gain)

16
Q

Is Oxidation state equal to Ionic charge ?

A

No.

Monatomic ions are the only species where charges and oxidation numbers coincide.

17
Q

What is the oxidation state of an uncombined element ?

A

In elementary substances, the oxidation number of an uncombined element regardless of whether it is monatomic, diatomic or polyatomic is always ZERO.

18
Q

What is the oxidation number of an Ion ?

A

In monatomic ions, the oxidation number of the element that makes up the ions is equal to the charge of the ion.

19
Q

What is the sum of the Oxidation numbers in a neutral molecule ?

A

Zero.

20
Q

What is the sum of the Oxidation numbers of a Polyatomic Ion ?

A

Equal to the charge of the Ion.

21
Q

What is the Oxidation number of Hydrogen ?

A

+1

22
Q

What is the Oxidation number of Oxygen ?

A

-2.

23
Q

What is the Oxidation number of the Alkali Earth Metals ?
E.g. Be, Mg, Ca, Sr

A

2+

24
Q

What is the Oxidation number of the Alkali metals ? E.g. H, Li, Na, K

A

+1

25
Q

Name 3 common reducing agents

A
  1. Lithium Aluminium Hydride LiAlH4
  2. Sodium Borohydride (NaBH4)
  3. Ferrous Ion (Fe2+)
26
Q

Name 5 common Oxidising agents

A
  1. Iodine (I2) and other Halogens
  2. Permanganate salts (MnO4)
  3. Peroxide compounds (H2O2)
  4. Ozone (O3), Osmium Tetroxide (OsO4)
  5. Nitric Acid (HNO3), Nitrous Oxide (N2O)
27
Q
A
28
Q
A